If she's no front teeth she maybe can't graze very effectively, so perhaps she would appreciate some hay or straw to munch on.
She would appreciate that

In fact though, once all the front teeth have gone, sheep can graze remarkably easily - if they bite you it's like being savaged by a gummy tortoise

. I have several ancients, up to 18 yo, and they happily munch away, as long as they have their molars, and no abscesses or the like. The most difficult time is when they are in the process of losing front teeth, so have some gaps and some wobblies. If possible it's best to pull out the wobblies when they're teetering (which doesn't seem to hurt) to give some firm teeth they can pull the grass with.
By the by - 9 yo isn't really old for Shetlands - they will happily produce a few more crops.